Dental-engine hand-tool.



W. G. SHELTON.

DENTAL ENGINE HAND TOOL.

APPLICATION FILED APR. I8. 19!!- 1,201,362.. Patented Oct. 17,1916.

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M Q 5 T F" 5,2 15 A INVE'NTOR WITNESSES:

WILLIAM GENIBY SHELTON, OF NEW YORK, N. Y.

DENTAL-ENGINE HAND-TOOL.

Specification of Letters Patent.

Patented Oct. 17, 1916.

Application filed April 18, 1911. Serial No. 621,746.

To all whom it may concern:

Be it known that I, WILLIAM GENTRY SIIuL'roN, a citizen of the United States, re-

siding in the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Dental-Engine Hand-Tools, of which the following is a. specification.

This invention relates to dental engines, and aims to provide certain improvements therein.

()ne of the objects of this invention is to provide a self-contained dental engine handtool, the arrangement and location of the parts being so organized that the tool balances itself properly in the hand, and is of such light and eflicient construction that it performs its work with the highest degree of satisfaction, one feature making for this satisfactory result being the location of the transmission gear rearwardly of the electric motor, the drill stock being carried at the front of such motor.

It is the object of the present invention to provide a dental engine adapted to be electrically operated, in which the motor is preferably located upon and carried by the dental hand-piece, and in which the controlling member of the drill or other tool is preferably arranged close to the hand of the operator.

In the preferred form of the invention the device is of extremely cheap and simple construction, light in weight, and easily moved from one position to another so that it may be conveniently operated in any position on either side of the patient.

The invention includes certain other improvements which will be hereinafter more fully pointed out.

Referring to the drawings, which illustrate one form of the invention, Figure 1 is a central vertical section; and Fig. 2 is a top or plan view.

A self-contained dental-engine hand-tool is shown in the illustration and is designated as a whole by the reference character A, and comprising a motor or engine portion B carried at the rear .of the dental handpiece or chuck meiber C. The motor or engine B comprises in the illustration an electric motor, the armature D of which is preferably mounted to rotate in line with the hand-piece C, within a stationary field E. The armature is shown provided with a hollow armature shaft I, extending forwardly and rearwardly of the motor. The armature and field are preferably arranged withm a suitably shaped casing F having at its lower end a hollow projection or bearmg G. Within the bearing G is arranged a fixed shaft H which extends u wardly within the armature so as to provi e a stationary bearing for the latter.

As the armature in this type of motor rotates at very high speed, which is not suitable for dental work, I provide a means for reducing the speed of the drill shaft to that which may be safely employed in dental operations. To this end the armature has fixedto' it the shaft I the rearwardly extending end of which is provided with a gear J which meshes with a pinion K fixedly mounted upon a countershaft L, the latter also carrying a small pinion M fixed tothe pinion K and which in turn meshes with a gear N fixed vupon a shaft 0 which passes through the hollow shaft I. In order to maintain the shaft 0 in position, it is formed with a groove P adapted to receive a set screw Q which permits the shaft to rotate while holding it against longitudinal displacement.

The hand-piece C is of some suitable form, and is provided at its lower end with a chuck or other means for engaging a drill stem, disk holder or the like. As such hand-pieces are Well known, it will not be here described in detail. It is suflicient to say that the hand piece is provided with a shaft R passing out of its rear end, to which is fixed one part S of a coupling member, the other part T of which is carried by the shaft 0. Such coupling member preferably includes a projection S which is adapted to fit into a recess in the member T, the coupling member S being also 'providedwith a socket S adapted to receive a centrally arranged spring nipple T. This form of coupling, which is well known, provides for a ready connection of the parts. The counter shaft L and shaft R together constitute a tool spindle mounted in the hand-piece and extending through the hollow armature shaft rearwardly of the motor. The transmission gearing between the said armature shaft and tool spindle is shown located rearwardly of the said motor,-that is assuming the hand-piece to be at the front of the hand-tool.

The motor casing is preferably supported by the shell of the hand-piece C, and to this end a sleeve U is preferably provided which is adapted to screw on the lower part of the motor casing and the upper part of the hand-piece as shown, such sleeve Covering the connection or joint between the shafts of the two parts. It is often desirable that the hand-piece C shall be capable of rotation relatively to or independently of the motor casing. This is particularly true in the use of angled hand-pieces. I therefore prefer to form the sleeve U in two parts, and to swivel these parts together as by the bead connection shown, or in any other suitable way.

My invention also provides means for controlling the operation of the drill or other tool, and this is preferably accomplished by a control of the motor, although other methods may be adopted for that purpose. In the construction shown I providean operating handle V, which is preferably located conveniently to the thumb of the operator, so that by an upward or downward movement the motor may be started, stopped or reversed. either of its extreme positions toward the center, will stop the motor, while a movement from its middle position to either end will start or reverse the motor, according to the arrangement of the parts. Many other constructions may be adopted for controlling the motor. It is desirable, however, that the controlling member shall be so located as to be within convenient reach of the operator, and preferably within reach of the hand of the operator which is holding the device.

It will be readily apparent that the transmission mechanism isof relatively light weight, and that the core structure of the motor is arranged closely adjacent the handpiece, whereby the center of gravity of the mechanisms carried by the hand-piece, and shown in the illustration disposed within the casing, is brought toward the hand of the operator when the instrument is in use.

In the construction thus described a very light and cheap form of motor may be used, and the entire device is of simple and A movement of the arm V from economical construction. Moreover the device is capable of use in any position, being restricted only by the length of the electric cable Xwhich is utilized to lead the current to the'motor.

While I have shown in detail one form of the invention, it will be understood that I do not wish to be limited thereto, as many changes may be made therein without departing from the spirit of the invention.

The feature herein illustrated of having the finger-piece extending along and entirely disconnected from the hand-piece, is claimed in my c'o-pending application, Serial No. 765,263, filed May 3, 1913.

\Vhat I claim is l. A dental-engine hand-tool comprising a dental hand-piece, an electric motor carried at the rear of the hand-piece and having its core structure arranged closely adjacent thereto and having a rearwardly extending armature shaft, a tool spindle mounted in the hand-piece and extending rearwardly of said motor, and transmission gearing between the said shaft and spindle and located rearwardly of the said motor, said transmission mechanism .being of relatively light weight.

2. A dental-engine hand-tool comprising a dental hand-piece, an electric motor carried at therear of the hand-piece and having its core structure arranged closely adjacent thereto, and having an armature shaft, a tool spindle mounted in the hand-piece, said shaft and spindle being 'mounted one within the other and extending rearwardly of said motor, and transmission gearing between the said shaft and spindle and located rearwardly of the said motor, said transmission mechanism being of relatively light weight.

In witness whereof, I have hereunto signedmy name in the presence of two subscribing witnesses.

WILLIAM GENTRY SHELTON.

I/Vitnesses:

EUGENE V. MYERS, FR D WHITE. 

